U.S. patent number 8,614,870 [Application Number 13/006,509] was granted by the patent office on 2013-12-24 for active transient current control in electronic circuit breakers.
This patent grant is currently assigned to Hamilton Sundstrand Corporation. The grantee listed for this patent is Huazhen Chai, Mustansir Kheraluwala, Jeffrey T. Wavering. Invention is credited to Huazhen Chai, Mustansir Kheraluwala, Jeffrey T. Wavering.
United States Patent |
8,614,870 |
Kheraluwala , et
al. |
December 24, 2013 |
Active transient current control in electronic circuit breakers
Abstract
A system and method for operating a semi-conductor based circuit
breaker as a transient current limiter includes a semi-conductor
switch that operates in a linear mode during a transient event and
thereby reduces the transient current passing through the
switch.
Inventors: |
Kheraluwala; Mustansir (Lake
Zurich, IL), Chai; Huazhen (Caledonia, IL), Wavering;
Jeffrey T. (Rockford, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kheraluwala; Mustansir
Chai; Huazhen
Wavering; Jeffrey T. |
Lake Zurich
Caledonia
Rockford |
IL
IL
IL |
US
US
US |
|
|
Assignee: |
Hamilton Sundstrand Corporation
(Windsor Locks, CT)
|
Family
ID: |
46397791 |
Appl.
No.: |
13/006,509 |
Filed: |
January 14, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120182656 A1 |
Jul 19, 2012 |
|
Current U.S.
Class: |
361/63 |
Current CPC
Class: |
H02J
4/00 (20130101); H02H 9/002 (20130101) |
Current International
Class: |
H02H
3/08 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Barnie; Rexford
Assistant Examiner: Brooks; Angela
Attorney, Agent or Firm: Carlson, Gaskey & Olds P.C.
Claims
What is claimed is:
1. A power distribution system comprising: a power bus; at least
one power distribution branch for providing power from said power
bus to an electrical system; a semi-conductor based circuit breaker
module mounted directly to said power bus and interruptably
connecting said power distribution branch to said power bus; a
controller capable of controlling said semi-conductor based circuit
breaker module in an off mode, a linear mode, and an on mode;
wherein said semi-conductor based circuit breaker module further
comprises a current limiting module such that said semi-conductor
based circuit breaker module can further operate as a current
limiter; and wherein said semi-conductor based circuit breaker
module further comprises a resistor/Zener diode (RZ) network
connected between a gate of a semi-conductor switch and an emitter
of said semi-conductor switch, thereby allowing said semi-conductor
switch to operate in a linear mode, and said at least one
resistor/Zener (RZ) network comprises multiple branches, each of
said multiple branches having a resistor in series with a Zener
diode.
2. The power distribution system of claim 1, wherein said
semi-conductor based circuit breaker module further comprises a
resistor/capacitor/Zener diode (RCZ) network connected between a
gate of a semi-conductor switch and an emitter of said
semi-conductor switch, thereby allowing said semi-conductor switch
to operate in a linear mode.
3. The power distribution system of claim 1, wherein said
semi-conductor based circuit breaker module further comprises at
least one uni-directional semi-conductor switch arranged such that
power can pass through said semi-conductor based circuit breaker
module in either a positive or negative direction.
4. A bus-mounted circuit breaker comprising: a semi-conductor
switch capable of operating in an off mode, a linear mode, and an
on mode; at least one resistor/Zener (RZ) network connected to a
control input of said semi-conductor switch, thereby allowing for
control of the semi-conductor switch in a linear mode and wherein
said at least one resistor/Zener (RZ) network comprises multiple
branches, each of said multiple branches having a resistor in
series with a Zener diode; a controller electrically coupled to
said control input of said semi-conductor switch; and wherein said
semi-conductor switch interruptably connects a power input and a
power output.
5. The bus-mounted circuit breaker of claim 4, wherein said
semi-conductor switch comprises at least one of an Insulated Gate
Bipolar Transistor (IGBT), a Metal Oxide Semiconductor Field Effect
Transistor (MOSFET), and a Bipolar junction Transistor (BJT).
6. The bus-mounted circuit breaker of claim 4, wherein said RZ
network is a resistive/capacitance/Zener (RCZ) network.
7. The bus-mounted circuit breaker of claim 4, wherein said circuit
breaker comprises two uni-directional semi-conductor modules, each
of said uni-directional semi-conductor modules having a
semi-conductor switch.
8. The bus-mounted circuit breaker of claim 7, wherein a collector
of a first uni-directional semi-conductor module is connected to a
collector of a second semi-conductor module, thereby enabling said
bus-mounted circuit breaker to operate bi-directionally.
9. The bus-mounted circuit breaker of claim 4, wherein said circuit
breaker comprises a bi-directional semi-conductor module having a
semi-conductor switch.
10. The bus-mounted circuit breaker of claim 9, wherein said
bi-directional semi-conductor module comprises a diode bridge,
wherein said semi-conductor switch connects a first diode junction
and a second diode junction, and wherein each of said first and
second diode junction have no other connections, thereby allowing
said semi-conductor switch to operate bi-directionally.
11. The bus-mounted circuit breaker of claim 8, further comprising
a Zener diode clamp, wherein said Zener diode clamp is connected in
parallel to said semi-conductor switch.
12. A method for actively controlling transient/inrush currents to
a load, comprising the step of operating a passive resistive/Zener
(RZ) circuit, wherein said passive resistive/Zener (RZ) network
comprises multiple branches, each of said multiple branches having
a resistor in series with a Zener diode, and a semi-conductor
switch in a linear mode, thereby eliminating a need for load side
current limiters and recognizing size and space savings.
13. The method of claim 12, further comprising the operating said
semi-conductor switch in an off mode when no through current is
required and when a fault is detected.
14. The method of claim 12, further comprising the step of
operating said semi-conductor switch in a fully-on mode as a
circuit breaker or switch.
15. The method of claim 12, further comprising the steps of:
detecting a start of a transient event; placing said semi-conductor
switch in the linear mode for a duration of said transient event;
and detecting an end of said transient event.
16. The method of claim 12, wherein said step of passing said
transient current through said semi-conductor switch operating in
the linear mode reduces said transient current.
17. The method of claim 12, wherein said semi-conductor switch is a
component of a bus-mounted semi-conductor circuit breaker.
18. The method of claim 12, wherein said passive RZ circuit is a
passive resistance/capacitance/Zener (RCZ) circuit.
19. The bus mounted circuit breaker of claim 4, wherein each of
said multiple branches is substantially identical.
20. The bus mounted circuit breaker of claim 4, further comprising
a capacitor connected in electrical parallel to each of said
multiple branches.
21. The bus mounted circuit breaker of claim 4, wherein said
resistor/Zener (RZ) network connects said control input to an
emitter of said semi-conductor switch.
22. The method of claim 12, wherein each of said multiple branches
is substantially identical.
23. The method of claim 12, wherein the step of operating a passive
resistive/Zener (RZ) circuit, wherein said passive resistive/Zener
(RZ) network comprises multiple branches, each of said multiple
branches having a resistor in series with a Zener diode and a
semi-conductor switch in a linear mode further comprises operating
a capacitor connected in electrical parallel to each of said
multiple branches.
Description
BACKGROUND
The present application is directed to incorporation of active
transient current control in electronic circuit breakers, such as
chip-on-busbar technology, for aerospace power distribution
systems. Conventional systems using electromechanical type circuit
breakers incorporate the active inrush current limiting in each of
the attached loads, such as motor controllers for the various
compressors, fans, pumps, etc.
Power distribution systems are used in aircraft, as well as other
vehicles, to distribute electrical power from a common source, such
as a power generator, to multiple different electronic systems each
having different power requirements. As is typical in electrical
systems, switching on an attached load can cause an undesirable
spike in electrical current flowing from a power bus in the power
distribution system to the load. This initial current spike is
either referred to as a transient current, or an in-rush current
from load stand point, or out-rush from Circuit Breaker stand
point.
In order to reduce the impact these transient currents have on the
attached electronics (loads) in a conventional system using
electromechanical circuit breakers, each of the loads includes a
transient current limiter that reduces inrush current to an
acceptable level.
SUMMARY
Disclosed is an active control method for controlling transient
currents using a semi-conductor switch/circuit breaker operating in
a linear mode.
Also disclosed is a bus-mounted circuit breaker having a
semi-conductor switch capable of operating in an off mode, a linear
mode, and an on mode. The bus-mounted circuit breaker also includes
a controller that is electrically coupled to a control input of the
semi-conductor switch. The semi-conductor switch interruptably
connects a power input and a power output.
Also disclosed is a power distribution system having a power bus,
at least one power distribution branch for providing power from the
power bus to an electrical system, a semi-conductor based circuit
breaker mounted directly to the power bus and interruptably
connecting the power distribution branch to the power bus, and a
controller capable of controlling the semi-conductor based circuit
breaker module in an off mode, a linear mode, and an on mode. The
semi-conductor based circuit breaker additionally has a current
limiting module such that the semi-conductor can further operate as
a current limiter.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure can be further understood by reference to the
following detailed description when considered in connection with
the accompanying drawings wherein:
FIG. 1 illustrates an example aircraft power distribution
system.
FIG. 2 schematically illustrates a power distribution system that
can be used in the example FIG. 1.
FIG. 3 illustrates an example bus mounted circuit breaker including
a semi-conductor switch.
FIG. 4 illustrates an alternate example bus mounted circuit breaker
including a semi-conductor switch.
FIG. 5 illustrates an example resistive/capacitive (RC) network
that can be used in the examples of FIGS. 3 and 4.
FIG. 6 illustrates an alternate example resistive/capacitive/Zener
(RCZ) network that can be used in the examples of FIGS. 3 and
4.
DETAILED DESCRIPTION
Typical vehicle power distribution systems utilize a centralized
power source, such as an engine, and a power bus to distribute
generated power to multiple different electronic systems (loads).
One such system, for use in an aircraft 10, is illustrated in FIG.
1. The aircraft 10 includes a generator 20 that generates power
using the rotation of the aircraft's engine according to known
principles. The generator 20 transmits the power to a power bus 30,
which distributes power to various loads 50 throughout the aircraft
10. To further facilitate the power distribution, the power bus 30
includes multiple bus-mounted on-board circuit breakers 40.
The bus-mounted on-board circuit breakers 40 are bus mounted
semi-conductor switches (or semi-conductor switch networks) that
are controlled by a controller 160. FIG. 2 presents a schematic
illustration of a power distribution system 100 that can be used in
the aircraft 10 of FIG. 1. The example power distribution system of
FIG. 2 can alternately be used in any power distribution system
utilizing bus-mounted on-board circuit breakers. As illustrated in
FIG. 2, multiple bus-mounted on-board circuit breakers 140 are
attached directly to the power bus 130 according to known
techniques. Power is transmitted through the bus-mounted on-board
circuit breakers 140 to the distributed electrical loads 150. In
typical power distribution systems, electro-mechanical circuit
breakers are used and are not directly mounted to the bus. In
addition to the electro-mechanical circuit breakers, typical power
distribution systems also require a transient current limiter in
each of the attached loads 150 in order to protect the loads 150
from transient currents.
Utilizing bus-mounted on-board circuit breakers 140, as in the
example of FIG. 2, allows the semi-conductor portion of the
bus-mounted on-board circuit breaker 140 to provide the additional
function of transient current limiting, with the addition of
minimal control components. Using the semiconductor portion of the
bus-mounted on-board circuit breaker 140 as a transient current
limiter allows the transient current limiting function to be
performed on the bus side of the system rather than in each of the
attached loads 150, thereby allowing each of the loads 150 to be
designed without an included transient current limiter. Shifting
the current limiting function to use preexisting components reduces
overall weight and cost, as well as recognizing efficiency
gains.
The power bus 130 also includes a controller 160 that includes
sensors that sense the power characteristics of the power bus 130.
The controller 160 controls each of the bus-mounted on-board
circuit breakers 140 based on the sensed characteristics. The
controller 160 can be a bus mounted device (as is pictured), or
independently mounted and draw power from a separate source. In the
case of a bus mounted controller 160, the bus-mounted on-board
circuit breakers 140 and the controller 160 can be a single
integrated circuit, or other form of a single electric component.
The controller 160 can control the bus mounted circuit breakers 140
according to known principles to perform the circuit breaker
function.
FIG. 3 illustrates an example bus-mounted on-board circuit breaker
200 (corresponding to bus-mounted on-board circuit breaker 140 in
FIG. 2) with additional circuitry that allows each semi-conductor
switch module 252, 254 in the bus-mounted on-board circuit breaker
200 to function as a current limiting module. The example of FIG. 3
uses two uni-directional semi-conductor switch modules 252, 254
arranged with a collector end 262 of the first module 252
transistor connected to a collector end 262 of the second module
254 transistor, thereby allowing current to flow either direction.
Additionally, a Zener diode clamp 242 is connected in parallel to
each of the switches 260.
Each module 252, 254 shares a single semi-conductor control signal
input 230, which controls the operating state of the semi-conductor
switch 260 based on the magnitude of the control current. The
semi-conductor control signal originates at a controller 160
(pictured in FIG. 2). The control signal is conditioned with two
conditioning resistors 244, 246, and a resistive/capacitive/Zener
(RCZ) network 240 prior to affecting the control of the
semi-conductor switch 260. The magnitude of the control current
reaching the semi-conductor switch 260 control input determines
which of three possible modes (off, linear, or on) the
semi-conductor switch 260 is operating in.
An alternate bus-mounted on-board circuit breaker module 300 using
a single uni-directional semi-conductor switch 360 is illustrated
in FIG. 4. As with FIG. 3, a semi-conductor switch control signal
330 is conditioned by two conditioning resistors 344 and 346 as
well as an RCZ element 340. A Zener diode clamp 342 is placed in
parallel to the switch 360. A network of diodes 350 is also used to
ensure that current will always pass through the semi-conductor
switch 360 in a single direction regardless of whether the current
is positive or negative. The diodes 350 are arranged in a standard
bridge formation according to known techniques. As with the example
of FIG. 3, the magnitude of the control current reaching the
semi-conductor switch 360 determines which of the three modes the
semi-conductor switch is operating in and allows the circuit
breaker module 300 to function as a current limiting module.
Referring to the examples of FIGS. 3 and 4, when a control signal
with a magnitude of zero reaches the semi-conductor switch 260, 360
control input the semi-conductor switch 260, 360 operates in an off
mode, and no power is allowed to pass through the semi-conductor
switch 260, 360. The "off" mode is utilized when the controller
determines a fault is present or when the controller 160 determines
that the circuit should be broken. In off mode, a corresponding
electrical load 150 is isolated from the power bus 130.
When a high control current (a control signal with a magnitude
exceeding a linear mode current level) reaches the semi-conductor
switch 260, 360 control input, the semi-conductor switch 260, 360
operates in an on mode. In the on mode, the semi-conductor switch
260, 360 allows power to pass freely, thereby enabling a direct
power path from the power source 210, 310, which is connected to
the power bus 130, to the electric load 220, 320. By switching
between the on and the off mode, the bus-mounted on-board circuit
breaker 200 can operate as a standard circuit breaker.
The third mode of semi-conductor switch operation is a linear mode.
The semi-conductor switch 260, 360 enters the linear mode when a
low, non-zero, control signal is supplied on the control input 230,
330. While operating in linear mode, the semi-conductor switch 260,
360 is configured as an active resistor with an equivalent
resistance of R. By operating the semi-conductor switch 260, 360 in
a linear mode during a transient event, the transient current is
reduced to an acceptable current level. In this way, the
semi-conductor switch 260, 360 functions as a current limiter in
addition to its function as a circuit breaker. This functionality
can be effected by placing the semi-conductor switch 260, 360 in
the linear mode when a transient event is detected, and returning
the semi-conductor switch 260, 360 to an on or off mode when the
transient event has ended. The transient event start and end are
detected by a controller 160 (shown in FIG. 2) using transient
event detection techniques known in the art.
While the gain in linear mode is fractional, the specific gain
depends on the magnitude of the control signal and the resistive
and capacitive values of the RC circuit 240 as described below. The
presence of the RCZ 240 further enables the adjustment of the gain
and affects the level of precision to match the non-linear gain
curve of a semiconductor switch.
The precision of the gain control in the linear phase is determined
by the RCZ 240, 340 implemented within the bus-mounted on-board
circuit breaker 200, 300. FIG. 5 illustrates an example simple RC
element 400 having a resistor 410 and a Zener diode 420. While the
above descriptions have an RCZ element 240, 340, the simplified
example omits the capacitor and thus is an RZ element. The dashed
elements 430 are provided for context, and are not components of
the RC element 400. The transient signal reduction (the gain) in
the example of FIG. 5 is approximated as a resistor having a
resistance R calculated using:
R=V.sub.1/I.sub.c+((R.sub.c+R.sub.1)/(R.sub.1*(I.sub.c/(V.sub.g-V.sub.1))-
)). With R.sub.c being the collector resistor 246, 346, R.sub.1
being the equivalent resistance of the resistive element of the RZ
network 400, I.sub.c being the collector current, V.sub.g being the
gate voltage of the semi-conductor switch 440, V.sub.1 being the
voltage drop across the Zener diode 420 of the RCZ element 400, and
R being the equivalent resistance.
The trans-conductance is non-linear, and the non-linearity can be
alternately approximated using two or three resistor-Zener
branches. An example using three resistor-Zener branches, each
having a resistor 510 in series with a Zener diode 520, is
illustrated in FIG. 6.
The inrush current control tolerance can be further reduced using
an RC ramp up control by adding a capacitor 530 between the gate
and emitter of the semiconductor switch 540. This effectively turns
active resistance into a varying resistance that dominates the
inrush current, thereby reducing the effects of trans-conductance
tolerances.
The example gain equation of FIG. 5 is shown using IGBT's as the
semi-conductor switch. Alternately, other semi-conductor
arrangements, such as BJT's or MOSFETs can be used. Alterations to
the formula for determining R for each of these alternate
arrangements can be determined by one skilled in the art using
known principles.
Although an example embodiment has been disclosed, a worker of
ordinary skill in this art would recognize that certain
modifications would come within the scope of the claims. For that
reason, the following claims should be studied to determine their
true scope and content.
* * * * *